Method of drying thread or the like



June 16, 1942. H. B. KITINE ET AL 2,286,213

METHOD OF DRYING THREAD OR THE LIKE Filed Sept. 29, 1959 v 4 Sheets-Sheet 1 INVENTORS HAYDEN B. KLINEAND BY L05 FRYER ATTORN Y June 16, 1942. I a KLlNE ETAL 2,286,213

I METHOD OF DRYING THREAD OR THE LIKE Filed Sept. 29, 1939 4 Sheets-Sheet 2 INVENTORS HAYDEN B. KLINEAND BY w FRYER ATTORNEY June 16, 1942. KLlNE AL 2,286,213

METHOD OF DRYING THREAD OR THE LIKE Filed Sept. 29, 1939 4 SheetsSheet 3 INVENTOR'S WWW ATTORNEY Patented June 16, 1942' UNITED srArEs-.. PATENT OFFICE METHOD OF DRYING THREAD OR THE LIKE Hayden B. Kline and Louis S. Fryer, Cleveland,

Ohio, assignors to Industrial Rayon Corporation, Cleveland, Ohio, a corporation of Deiaware Application September 29, 1939, Serial No. 297,074

(on. re-54) 6 Claims.

This invention relates to methods which may be used in manufacturing and/or processing strip material such as thread or the like -(hereinafter referred to as thread).' More particularly, the invention is directed to methods which may be employed advantageously in the manufacture and/or processing of textile thread to control certain of the physical and physico-chemi'cal properties thereof; e. g.,'shrinkage, dyeing and'other characteristics. The invention is especially useful in the manufacture by a continuous process defined as the amount by which a dry, finished thread will shrink, if unrestrained in any manner, upon being rewet and redried.

For example, a textile thread, to be Commercial textile thread employed in weav- 1 ing, particularly for use as a weft thread, should be of such low residual shrinkage capacity as to preclude the possibility that the fabric woven therefrom will shrink by more than a very small amount, if at all, during the subsequent finishing operations. The finishing operations ordinarily consist of washing, dyeing, etc., after which the' fabric is usually dried in rigid tentering frames which hold the fabric to the desired finished width. If the residual shrinkage capacity of the thread from whichthe fabric is woven exceeds very low limits, the tendency of the fabric to shrink stresses the thread, causing barr effects to develop in the fabric and in some cases causing the fabric to be torn from the tentering frames. In either case, the commercial value of the fabric is seriously impaired.

Furthermore, weaving thread should have throughout its length a uniform, and preferably high, afiinity for dyestuffs. Uniformity of dye affinity is important inasmuch as a woven fabric formed of thread which does not possess the desired uniformity usually embodies defects of the barr which deleteriously affect the commercial acceptability of the fabric. It is desirable to produce a thread having high dye aflinity because it recently, all viscose artificial silk thread was protype known to the trade as shiners" or dye requires less time and handling to secure the desired depth of color in the finished fabric woven from such thread and because the fastness of the dyestuff is improved.- I

For purposes of illustration, but in no sense of limitation, certain of the features of the invention will be described hereinafter in connection with the manufacture of multiple filament viscose artificial silk thread.

Viscose artificial silk thread comprises hydrated cellulose regenerated from a solution of sodium cellulose xanthate (viscose). Coagulation is brought about by extruding the'solution I through a plurality of minute orifices into an acid precipitating bath, an operation which gives rise to a delicate thread consisting of a plurality of filaments that, at least at this stage, are more or less gelatinous in nature. Subsequent to coagulation, the thread is ordinarily subjected before it is initially dried to suitable processing treatments including washing, desulphurizing, etc. During these operations and in fact until such time as it is completely solidified and dried, the thread is usually considered to be in a gel state,

Great care must be exercised in processing thread while it is in the gel state inasmuch as its 'physico-chemical properties are markedly affected by the nature of the processing treatments, as well as by the manner in'which the treatments are administered to the thread. It has been found, for example, that the manner of drying the thread initially; i. e., from the gel state, determines to a large extent the final characteristics'of the finished thread, particularly its dyeing properties. This is equally true whether the thread is. manufactured by the socalled continuous process or according to the discontinuous methods of production by which, until duced.

Among. other things, the tension imparted to the thread during its drying from the gel state affects the physico-chemical characteristics of the thread. For example, if thread is dried in the spool package in which it is collected in the spool-spinning process, uneven dyeing properties result. Such non-uniformity results from the fact that shrinkage of the innermost layers of thread is prevented by the presence of the spool, while the faster drying outer layers of thread are prevented from shrinking only by the slower drying intermediate layers. Different portions of the thread are differently stressed, resulting in widely varying dye aflinities. As a rule, such irregularities render'spool-drled thread unfit for weaving purposes unless special precautions are taken to improve its uniformity.

To overcome these difficulties, it has been the usual practice in the manufacture of weaving thread by discontinuous processes to dry the thread in the form of a skein containing several thousand yards of thread. The skeinsare usual ly formed by unwinding the thread from the package in which it was collected and rewindin it into skein form, in which state the thread can be supported so that it hangs substantially free of tension during drying. The thread can therefore shrink freely, wherefore it has a low residual capacity to shrink; however, even such skeindried thread does not have absolute uniformity, this for the reason that the outer windings of the thread in the skein tend to dry more rapidly than the intermediate windings and therefore subject the thread to tension differences which affect its dye aflinity.

On the whole, the discontinuous production of viscose weaving thread is unsatisfactory because of the high cost of production, the waste of the thread due to injuries resulting from repeated handling, and the long periods of time required in processing. The completed product does not possess the desired uniformity of shrinkage, dyeing and other characteristics, so that in general it is not capable of measuring up to the extremely high standard of quality which is desired. For such reasons, to produce viscose weaving thread commercially by a continuous process wherein such disadvantages are eliminated has long been recognized as a desideratum.

However, the continuous production of viscose artificial silk thread involves other problems not.

present in discontinuous methods of production. Such problems arise primarily out of the fact that in the continuous process thread in the finished state is produced from liquid viscose in a. very small fraction of the time required in discontinuous processes. Whereas in discontinuous processes thousands of yards of thread wound in a package are subjected to processing conditions for many hours or even days, in the continuous process not more than a few yards of thread are subjected to a given set of processing conditions simultaneously. In particular, the shortness of the time available for the initial drying of the thread from the gel state is a factor causing difliculties in the manufacture of thread by a continuous process.

In the continuous process of manufacture, it has been found that the rapid initial drying of the thread from the gel state does not give rise to a permanently low shrinkage capacity, this even if the thread is permitted to shrink during such drying operation. The residual shrinkage capacity of thread dried under such conditions is-often so high that the thread is not well adapted to weaving on looms producing fabrics of widths approximating the intended finished width of the fabric. These difliculties are probably related to the fact that in the continuous process the thread is dried in only a few seconds or, at the most, a minute or two. Such difliculties are not found in the manufacture of weaving thread by discontinuous processes. 1

It; has therefore been thought that, while the continuous process constitutes a very great improvement over the discontinuous processes in respect of uniformity of the thread, amount of labor required, and reduced production time, it does not lend itself to the production of thread of However. the present invention, in addition to obviating the numerous disadvantages of the dis-' continuous process, gives rise to a thread which is eminently suitable for weaving, which is of a particularly high degree of uniformity of physical and physico-chemical characteristics, and which is characterized by a permanently low residual shrinkage capacity. The invention makes these results possible by repeatedly drying and rewetting the thread in a continuous process while permitting it to shrink, all as more fully explained hereinafter. For convenience, the invention will be described as applied to the manufacture of multiple filament viscose artificial silk thread on apparatus operating on the principle of that shown, described and claimed in copending application Serial No 7,114, flied February 18, 1935 (Patent 2,225,642).

In the drawings, Figure 1 represents a sectional elevation of one form of apparatus in which the invention is embodied. Figure 2, which represents a portion of the apparatus of Figure l on an enlarged scale, shows the means for repeatedly wetting and drying the thread according to the invention. Figure 3 illustrates on the same enlarged scale a similar portion of modified apparatus likewise embodying the invention. Figure 4 is an end elevation of one form of thread-advancing reel employed to dry the thread. Figure 5 represents a sectional elevation of said reel from line 55 of Figure 4. Figure 6 is a sectional elevation of another type of thread-advancing reel employed to dry thread after intermediate rewetting.

a permanently low residual shrinkage capacity.

Figure 1 shows a complete machine for continuously manufacturing multiple filament viscose artificial silk thread of low residual shrinkage capacity in accordance with the teachings of the present invention. Said apparatus, a portion of which is shown in greater detail in Figure 2, is adapted to produce a large number of threads simultaneously, each by the extrusion of viscose from a spinneret 2 disposed in a coagulating bath 3 contained in trough 4. Each thread 1 passes to a thread-advancing reel 5, the same being the first of a concatenate series of thread-advansing reels designated 5 to 14, inclusive.

In the apparatus of Figures 1 and 2, the threadadvancing reels 5 to 14, inclusive, take the form of reels of cantilever construction operating on the principle of that described in said copending application No. 7,114 (Patent 2,225,642). Each of reels 5 to M. inclusive, advances the thread toward the unsupported end thereof in a large number of closely spaced, generally helical turns. On said reels suitable liquid processing operations such as washing, desulphurizing, etc., are performed on the thread. after which the thread is dried. From the last reel I4, the thread passes to suitable collecting apparatus, such as the cap-twister l6, which collects the finished thread in package form. a

In said apparatus, each thread-producing unit. comprises a spinneret, a descending series of reels 5 to H, inclusive, and an associated cap-twister. The reels in each descending series are disposed in stepped arrangement with the unsupported or discharge end of each preceding reel in apposite relation to the supported or receiving end of the succeeding reel, the unsupported ends of ,all reels extending in the same direction. A plurality of such thread-producing units is disposed on each side of the apparatus; so that the apparatus as a whole has two operating faces, one on each side thereof. Corresponding parts of all units on each the apparatus on each side thereof.

side of the apparatus are therefore in correspondrarily stored in order to provide suificient time for' the thread to achieve the desired degree of coagulation before it is subjected to subsequent proc-- essing treatments. The thread'then passes from the unsupported end of reel to the supported end of succeeding reel t.

On reel 6. the thread may, if desired, be subjected to the action of an additional coagulating liquid. Wash water may next be applied to the thread on reel I, after which any free sulphur which may be produced in the threadas a result of the regeneration process may be removed by the A shown, described and claimed in copending application Serial No. 24l,222,.filed November 18,

application to the thread on reel 8 of a suitable I desulphurizing liquid. Thethread may be washed again on reel 9 to free it of the desulphurizing medium and, if desired, may be bleached on reel III. The thread I then passes to reel I I on which it may again be washed.

In the embodiment of the invention illustrated in Figures 1 and 2, the liquid to the actfin of which the thread is subjected on reel 6 is supplied.

from a reagent distributor II communicating with a supply pipe I8 which extends-longitudinally of Similarly, the liquid supplied to each of the succeeding reels I to II, inclusive, is applied to the thread from a reagent distributor II communicating with a conduit I9 which extends longitudinally of the machine, being formed integrally with the lower porterruptedly' around the entire thread-bearing periphery of the reel. In the illustrated apparatus, the reels are inclined to the horizontal in order that such film of liquid may travel along each reel from the unsupported end toward the supported end thereof, thus providing a countercurrent flow of liquid which more effectively processes the thread. Although these conditions do not occur on reels I2 and I3, it is convenient from a constructional standpoint to tilt them also.

According to the present invention, after the aforementioned treatments have been performed, the thread'is dried on reels I2, I3 and I4, as explained hereinafter.

. After thread I has been completely processed, it is passed from the last reel It to cap-twister I6 by means of which it is twisted and collected. The collecting apparatus comprises a continuous belt 22, driven by rotating drum 23, which belt,

guided by suitable pulleys, passes around the whirls 2d of cap-twisters I6 on opposite sides of the apparatus, thus rotating the bobbins 25' mounted on the whirls of such cap-twisters. Lifter rails 26 actuated by a suitable cam mechanism (not shown) reciprocate bobbins 25 into and out of caps 2i of the cap-twisters, thus twisting the thread and collecting it on bobbins 25 in package form. Such cap-twisting apparatus 1938 (Patent 2,203,665).

According to the invention, thread which has been formed as above described but which is still in the gel state is subjected to repeated drying with intermediate rewetting on a plurality of reels under conditions permitting shrinkage of the thread in the course of atleast one drying operation. During the time that the various liquid processing treatmentsare being administered to the thread on the reels prior to reel I2, the thread is always in the gel state. On reel I2, however, the thread is subjected to its initial drying operation, being dried by means of heat,

applied to, the reel from the interior thereof. After being dried on reel I2, it is rewet, stored under conditions such that excess liquid carried by the thread may drip therefrom on reel I3, and dried once again on reel It.

While various modifications thereof may be employed, the apparatus shown in Figure 2 has been found to be extremely satisfactory for these purposes.

In said apparatus, each of the drying reels I2 and M is formed of metal, being heated internally thereof by the means hereinafter described. The thread passing from reel II to reel I2 is substantially completely dried on reel I2, but just before it leaves said .reel at the unsupported end thereof it is subjected to the action of a small stream of an aqueous rewetting liquid supplied from reagent distributor 29. The liquid thus applied to the reel is not suflicient in amount to spread over the reel but only to wet the last few turns of thread on the reel; however, the amount-of liquid is sufficient to wet the thread thoroughly. -'I'he wet thread then passes to the reel I3 which, in the embodiment of the invention illustrated in Figure 2, constitutes a drip reel.

No processing medium is applied to the thread -on reel I3; instead, the liquid applied to the thread just before it leaves .reel I2 is permitted to drip therefrom. In, view of the length of thread which is stored in this manner, drops of excess moisture carried by different portions of the thread which would otherwise tend to impair the uniformity of the subsequent drying operation may be removed by simply permitting them to chip from the thread. A mild evaporative action also takes place due to the exposure of the thread to the air. Consequently, when the thread reaches the discharge end of reel I3, all portions of the thread have thesame or substantially the same moisture content.

The thread passing to reel It, having a substantially uniform moisture content, may be uniform-' 1y dried on reel It provided that uniform drying conditions are applied to the thread. To aid in maintaining uniformity of drying conditions, an enclosure 30 is provided surrounding each reel Id. Said enclosure comprises a stationary portion 3| and a hinged closure portion 32. Slots 33 and 34 are provided at the junctions of the hinged and stationary portions to permit the thread I to enter and leave said chamber in passing to and from reel It. If desired, a similar enclosure ma of course, be provided for reel I2.

Among other things, the invention contemplates that shrinkage'of the thread shall be permitted to take place as hereinafter described for the purpose, for example, of imparting the deforms no part of the present invention, but is sired low residual shrinkage capacity to the thread.

During the initial drying of the thread on reel I2 a certain amount of shrinkage tends to occur in the thread. It has been found advantageous, but not at all necessary, to decrease the diameter of reel l2 progressively as the thread travels to- I the thread in this manner, the dye amnity of the thread is favorably influenced, the thread dyeing somewhat darker than otherwise would be the case.

It has been found that a slight elongation of the thread occurs when it is rewet. In the apparatus illustrated, this is compensated for by rotating the reel ii, to which the thread passes after it leaves reel .12, at a peripheral speed sufficiently greater than that of the discharge end of reel 52. With that in mind, reels 6! and I! are rotated at the same angular speeds, but the diameter of reel 13 at its supported end is slightly larger than that of reel. II at its unsupported end. Preferably, the ratio of the diameters is such that neither tension nor slack is developed in the thread passing from reel H to reel it. The same eflect may, of course, be obtained with reels of equal diameters by imposing a suitable diflerence on the angular velocities of the reels.

No appreciable shrinkage of the thread occurs while it is stored on reel l3; consequently, reel i3 may be formed with no variation in the diameter thereof.

Reel ll, however, is preferably provided with a contour of a character such that as the thread dries it may shrink freely. This is accomplished by forming the periphery of the reel so that it conforms closely to the shape of the diminishing helix which the thread tends to develop as it shrinks. It is known, for example, that the thread does not begin to shrink as soon as it comes into contact with reel ll, wherefore the reel may,as shown, be made substantially cylindrical for a considerable portion thereof. During this portion of the drying operation, external moisture only is being removed from the thread, the removal of which does not result in shrinkage of the thread.

Thereafter the internal moisture is removed, which results in marked shrinkage of the thread; acordingly, the reel H 'is tapered over the intermediate portion thereof. The minimum diameter of the" tapered portion of the reel is such that suillcient shrinkage is permitted by the time the thread reaches the -end of the tapered portion to impart to the thread the desired low residual shrinkage capacity. If desired, the tapered portion of the reel may be so formed that the dried thread has virtually no residual shrinkage capacity whatsoever.

The final portion of the reel, which is of substantially cylindrical form, serves among other things to insure substantially equal drying of the thread throughout its length. For example, portions of the thread which have not been as completely dried as other portions are enabled to complete their drying on such cylindrical portion before they leave the reel. In general, it is desirable that the thread leaving this portion of the reel have a final moisture content in the neighborhood of 10%, more particularly since a moisture content of this order, especially at elevated temperatures, greatly facilitates twisting the thread.

Reel M, as also reel i2, may advantageously have a contour conforming generally to that shown and described in copending application Serial No. 107,667, filed October 26, 1936 (Patent 2,203,686). The reel of said copending application is so designed that the diameter of the reel in eflect diminishes in the direction of travel of the thread more rapidly than the diameters of the thread turns tend to diminish as a result of shrinkage of the thread. Consequently, substantially unrestrained shrinkage of the thread is possible in spite of unintentional variations which sometimes occur in the intensity of the drying conditions to which the thread is subjected on the reel.

According to the present invention, the apparatus as a whole is preferably so designed that little, if any, tension exists in the thread during the various drying, rewetting and redrying operations, such slight tension as happens to be present being substantially constant. This may be accomplished by relating the peripheral speeds of the various reels so that, although slack due to elongation is taken up, no stretch is imparted to the thread. The amount of tension to which the thread is subjected and the amount of shrinkage permitted in the thread during the second drying operation; i. e., while it is bein dried on reel It, has a great deal to do with the residual shrinkage capacity of the thread.

The apparatus illustrated as embodying the invention also includes another feature which is extremely useful in producing low residual shrinkage capacity in thread which is being dried continuously; namely, means for maintaining the thread for a substantial period at high temperatures under conditions of high moisture content. By such means, what may be called a cooking eflect is imparted to the thread. Such effect apparently plays an important part in the reorientation of the micellar structure of the thread necessary to obtain substantially complete shrinkage thereof at the high drying speeds employed in the continuous processing of viscose artificial silk' thread.

In the embodiment of the invention illustrated in Figures 1 and 2, a pronounced cooking effect is produced at the unsupported end of reel II: at that point, an aqueous rewetting liquid is applied to the thread while the thread is still at the relatively high temperature of the reel. To aid in the cooking effect, a higher temperature may be employed on reel l2 than on reel ll; indeed, it has been found desirable to maintain the temperature of the drying reel 12 considerably above the boiling point of the rewetting liquid; i. e., at a temperature in excess of C., and to maintain the temperature on drying reel it below the boiling point of the rewetting liquid, since this permits a more nearly complete shrinkage of the thread. In the practice of the invention, the rewetting liquid may be either cold or hot, but is preferably employed only after being first heated to a temperature approaching the boiling point of water.

The idea of continuously cooking the thread in the course of the continuous drying operation forms no part of the present invention but is described and claimed in copending application Serial No. 296,930, filed September 28, 1939, by Louis S. Fryer, Emerson B. Helm, and Kenneth M. McLellan.

While the embodiment of the invention shown in Figures 1 and 2 is preferred, apparatus embodying the invention in modified form may also be employed. Thus in Figure 3, which represents a portion of a continuous processing apparatus generally similar to that shown in Figure 2, the rewetting liquid is not applied to the thread on the reel l2, but is applied to the thread after it leaves said reel. More specifically, the rewetting liquid .is applied to the first few turns of thread on reel l3. It is applied by means of a reagent distributor 29a supplied from a conduit |9 forming part of the trough 2| disposed below the preceding reel. The remainder of reel I3, on which portion no liquid of any kind is applied to the thread, serves as a drip stage for equalizing the moisture content ofthe thread, precisely as has been explained above in connection with reel i3 of Figure 2.

The rewetting liquid applied to thethread on rel l3 may be at room temperature but preferably is heated, since this produces a cooking effect generally similar to that produced at the unsupported end of reel it in the embodiment of the invention shown in Figure 2. However, somewhat better results are obtained when the 'rewetting liquid is applied to the thread while the thread itself is heated. In the embodiment of Figure 3, the reel i2 is shown as having no taper to compensate for the tendency of the thread to shrink, each reel member being substantially cylindrical in form. As has been explained above, tapering reel i2 has relatively little efiect on the residual shrinkage capacity of the thread. In all other respects, the embodi- As is apparent from Figures 4 to 6, inclusive,

each of reels i2 and it comprises two wholly rigid reel members, each such reel member being of substantially circular cross section. Each reel member has a periphery made up of a plurality of longitudinally extending bar members which are interleaved with the bar members of the other reel member. The two reel members rotate about axes displaced from and inclined to each other in such manner as to advance the thread in a large number of closely spaced, generally helical turns from the supported end to the unsupported end thereof.

Reel l2, as can be seen from Figures 4 and 5, comprises two rigid reel members 35 and 36 each of which substantially circular in cross section. Member 35, which may be termed the concentric member, is mounted concentrically upon and for rotation with hollow drive shaft 31. Its periphery is made up of a plurality of spaced, longitudinally extending bar members 33. Member 36, which may be termed the eccentric mem her, is rotatably mounted with its axis inclined to but in a plane slightly offset from the axis of reel member 35. Its periphery includes a plurality of spaced, longitudinally extending bar members 39 alternately disposed with respect to bar members 38 of concentric reel member 35.

Concentric member 35 may be formed as shown with the bar members 38 integral with hollow body portion 4 0. In the illustrated reel, front and rear members 4| and 42, respectively, form fluid-tight junctions with hollow body portion 40. Said members also surround hollow shaft 31. Cooperating annular sealing members 43 disposed in recesses 44 in members 4| and 42, which sealing members are wedge-shaped in cross section, operate to prevent the escape of reel, is threaded into a plug 41 welded in the unsupported end of hollow shaft 31. A washer 48, disposed on shaft'31 as by means of the snap ring 49 shown, bears against the outer sealing member 43 at the rear of the reel member 35, serving thereby to locate reel member 35 endwise on the shaft. As bolt 45 is tightened, it forces the wedge-shaped members 43 together at both ends of the reel .member 35, thus effectively sealing the reel member 35. The tight fits at these points on shaft 31 also provide the necessary driving engagement of member 35 with said. shaft.

In the reel of Figures 4 and 5, eccentric member 36 is formed of a rigid cagelike member 5|! mounted concentrically upon a rotatably mounted supporting member 5|, as by bolts 52. Rigid cagelike member 50 comprises the aforementioned bar members 39 which are fixed at their s pported ends to an external annular supporting rib 53 by means of which the cagelike member 50 is mounted on said supporting member 5|. An annular reinforcing member 54 is fixed to the bar members 39 at their unsupported ends. Supporting member 5| is mounted on frame member 55 for rotation about an axis disposed inthe desired offset and inclined relationship with respect to the axis of rotaton of concentric member 35.

Supporting member 5| is formed so that projecting boss 55 of frame member 55, on which said member 5| is rotatably mounted by means of spaced antifriction bearings 51, is disposed within the reel proper. To this end, the rear closure member 32 of the concentric member 35 is so positioned that the boss 53 can be disposed within the reel member 35. The purpose of this arrangement is to provide a construction such that, although the fluid supply and removal means are associated with said frame member 55, the overall length of the reel and its supporting'member is only slightly, if at all, greater than one of the liquid processing reels 6 to H inclusive. Thus, a reel of this type can be substituted, if desired, for any one of the liquid processing reels.

Reel 02 is similar to the liquid processing reels in that its frame member 55 is provided with a flanged portion 58 adapted to be held by set screws 50 in a cup 59fixed to frame 10 of the apparatus (Figure 2).

Drive shaft 31, on which concentric member 35 formed of a metal such as aluminum which is chosen for its high heat conductivity, would otherwise wear easily.

31f meshes with bevel gear 66 mounted on vertically inclined drive shaft 61; similarly, each of the other reels 6 to l4, inclusive, is driven from drive shaft 61.

Bevel gear 65, fixed to the rear end of shaft Reel i2 is heated by the circulation of a suitable heating fluid through the hollow body portion lb of concentric reel member 35. As is apparent from'Figure 5, the frame member 55 is hollow, being constructed in such manner that it includes two compartments 68 and 69 through both of which passes drive shaft 31. Suitable sealing means H are provided to prevent the escape of fiuid past the drive Shaft from the interior of said compartments either from one compartment to the other or to the atmosphere.

' The sealing means include a smooth-faced stationary member I2 against which bears a rotatable bearing member 13 urged thereagainst by a spring 14. Spring 14 is compressed between a flexible annular sealing member I seated on member I3 and a support 16 rigidly fixed t0 the drive shaft-31, as by a set screw TI. The support 16 in compartment 68 serves both seals N therein, while the support 16 in compartment 69 serves a single seal. Said seals aid in locating the drive shaft 31, and consequently the reel member 35, endwise of the reel.

Compartment 68 is provided with an opening 18 through which heating fluid is supplied from tube 19 connected to frame member 55. The heating fluid passes through a port 88 in the wall of hollow drive shaft 31, thence longitudinally of said drive shaft, andfinally through port 82 into the interior of hollow body portion 48. The heating fluid passes out of said hollow body portion 40 through an opening 83 in hollow drive shaft 31 which opening communicates with an interior tube 84 rigidlylfixed in said drive shaft.

The plug 41 at the unsupported end of hollow drive shaft 31 serves to separate the inner tube and the drive shaft and to prevent fluid from passing directly from the drive shaft to the tube or vice versa. A similar plug 85 at the rear portion of said drive shaft 31 prevents the intermixing of the entering and discharging fluid. The

fluid passes from said inner tube 84 through port 86 into the rear compartment 69, from which it passes'out through opening 81 to a discharge tube 88.

' In the apparatus shown in Figure 2, supply tube 19 is connected to a supply conduit 88 which extends lengthwise of the apparatus in such manner as to permit it to serve a plurality of reels I2 disposed lengthwise of the machine as a whole. Similarly, discharge tube 88 communicates with a discharge conduit 88 which extends lengthwise of the apparatus to permit it to accommodate a plurality of reels l2. Regulating valves 32 may be provided, as shown, to control the flow of heating fluid through the reel l2. The heating fluid may be hot water, steam or any other suitable fluid which may be heated and circulated through the system. Other heating and circulatin means than that illustrated may of course be employed.

The reel member 35 and the bar members 38 thereof are thus directly heated by the fluid circulated therethrough. The other reel member 36, and particularly the bar members 38 thereof, are heated by radiation and conduction from concentric reel member 35. This arrangement is particularly efllcient for drying thread, which is one reason why reel I2 is preferred for use in the apparatus. of the invention. However, reel l2 per se constitutes no part of the invention, being the subject matter of copending application Serial No. 296,937, filed September 28, 1939; by Richard F. Bergmann.

Reel I4 is similar in many ways to reel 12 and operates in a generally similar manner. As appears from Figure 6, it comprises two wholly rigid reel members 35a and 36a. Concentric member 35a, the periphery of which is defined by a plurality of spaced, longitudinally extending bar members 3811, is mounted concentrically upon and for rotation with hollow drive shaft 31a. Member 36a, which may be termed the eccentric member, is rotatably mounted with its axis slightly offset from and inclined to that of member 35a. Its periphery includes a plurality of spaced, longitudinally extending bar members 3911 alternately disposed with respect to the bar members 380 of reel member 35a.

Concentric member 35a is formed as shown with its bar members 38a integral with a hollow body portion 48a. Members Ma and 42a, forming fluid-tight junctions with said body portion, 40a, not only close off the ends of said body portion but serve as means for mounting the reel member 35a on drive shaft 31a. Reel member 35a is held on drive shaft 31a against a collar 49a, iixed'to said drive shaft, by bolt 45a, threaded into the end of said drive shaft. Packing 93, which is disposed in a recess a, in member 42a, is compressed against collar 49a in order to prevent the escape of heating fluid from the interior of body portion 40a.

Eccentric reel member 36a is formed of a rigid cagelike member 58a concentrically mounted upon a rotatable supporting member 5M by means of bolts 52a. Rigid cagelike member 58a comprises the bar members 39a fixed at their supported ends to an external annular reinforcing rib 53a, by means of which said cagelike member 58a is mounted on rotatable supporting member 5| a, and an annular reinforcing rib 54a fixed to the bar members 39a at, their unsupported ends. Supporting member 5 la is mounted by means of spaced antifriction bearings 51a upon frame member 55a for rotation about an axis disposed in the desired offset and inclined relation with respect to the axis of rotation of concentric member 35a.

An externally toothed member 84a -on rear closure member 42a engages an annular internally toothed member 63a on supporting member 5la, thus driving eccentric reelmember 36a from concentric reel member 35a.

Drive shaft 31a is journalled in frame member 55a by means of bearing Ola disposed at the unsupported end of said,frame member and by meansjof antifriction bearing 62a supported in a cross member 84 fixed to the spaced, longitudinally extending members 95 forming part of frame member 55a. It is positioned against endwise movement between collar 48a and collar 98 bearing against the inner race of antifriction bearing 62a. Drive shaft 31a is rotated by means of a bevel gear a mounted on said shaft between the longitudinally extending members 95. Bevel gear 65a meshes with a corresponding gear on inclined drive shaft 61. I

Frame member 55a is provided with a flanged portion 58a adapted to fit closely into and to be held in a cup member 59a fixed to the frame of the apparatus, whereby reel H is demountably supported in the apparatus.

The means for circulating heating fluid through the reel is generally similar to that above described. A fitting 31 mounted on the longitudinally extending members 85 of frame'member 55a is provided with. two compartments 68a and 63a. The drive shaft 81a projects into the forward compartment 68a, while tube 84a, fixed in said hollow drive shaft 31a, extends into rear compartment 69a. Suitable plugs 41a and 85a are provided in said" hollow drive shaft 311; to

has been dried but while itis still at an elevated temperature. The rewetting is preferably done by applying the liquid to the thread at the rate of about 30 cc. per minute, the rate being detersupport inner tube 84:; and prevent fluid from mined by the amount of moisture which can passing directly from hollow drive shaft 31a to reabsorbed by the thread. The thread W111 ordiinner tube 84a and vice versa. Suitable sealing means Ha, are provided to prevent the escape of fluid from compartment 68a past driveshaft 31a or from compartment 69a into compartment 68a. 10

Heating fluid is supplied to compartment 68a through opening 18a and passes through ports Bla into the space between the inner tube. 85a

and the inner surface of hollow drive shaft 31a.

The fluid passes' out of said hollow drive shaft through ports 82a into the interior of body portion 40a of concentric reel member 35a. After circulating through said body portion, the fluid passes through ports 83a into the interior of inner tube 84a, whence it is discharged into the 20 rear compartment 69a. The heating fluid passes out of said compartment through port 810.

In the embodiment of the invention shown in Figure 2, heating fluid is supplied through conduit 89a which extends longitudinally of the machine. Tube 19a conducts the heating fluid from conduit 89a to entrance port 18a of reels M. After the heating fluid has circulated through thereel, it passes through a tube 88a connected to the discharge port 81a to a discharge conduit 90a extending longitudinally of the apparatus. The

heating fluid for reels l4 may comprise any suitable medium such as hot water, steam or other suitable fluid.

Using the methods and apparatus of the invention, it is possible to produce by a continuous process multiple filament viscose artificial silk thread having a highly uniform residual shrinkage capacity in the neighborhood of one per cent.

The precise value in'agiven case depends upon 40 various factors, but will usually be found to be within the range between three quarters and .one and one quarter per cent. All other physical and physico-chemical characteristics are likewise exfilaments, is delivered at a speed of 68 meters per minute to reel 82, which is preferably made of aluminum. Still, in the gel state when it is passed to the reel, the thread has a moisture content ofapproximately 400%. The thread is at ordinary room temperatures before it is taken up by the reel, which is heated to at least 115 0.;

so that it is subjected on the reel to a sudden rise in temperature of approximately 90 C.

At the high temperature to which the reel is heated, the moisture is rapidly driven from the thread. The thread advances several. turns before it begins to shrink; accordingly, the reel is of substantially cylindrical configuration for about 1.5! lengthwise of its thread-bearing periphery, measuring from the supported end of the reel. From this portion, where the reel is of 5" diameter, the reel is tapered to a diameter of approximately 4.9", this in order to allow for shrinkage of the thread during the phase of. the

drying operation during which the internal moisture is removed from the thread.

The last few turns of thread at the unsupported end of the reel: i. e., for a distance of about A" lengthwise of the periphery of the reel, are rewet with an aqueous rewetting liquid after the thread )inclusiv'e. configuration throughout its length, having a narily absorb the rewetting liquid only until it attains a moisture content slightly in excess of 200%.

The application of the rewetting liquid results in elongation of the thread, wherefore reel 13 is 5" in dameter at the portion on which the thread starts. It revolves at the same angular velocity as the preceding reel, the difference between the 5" diameter of reel 13 and the 4.9" diameter of reel l2 being sufficient to allow the thread to .pass from reel I2 to reel l3 without slackness or tension. Reel l3, being formed of hard rubber or other plastic material, is not heated, but is of the same "type as reels Sto H, The reel is of substantially cylindrical thread-bearing periphery in the neighborhood of 5" long.

As it leaves reel-l3, the thread has a highly uniform moisture content of approximately 200%, based on'the weight of the thread.

Reel I, on which the final drying of the thread is'accomplished, is ordinarily designed to be heated to a temperature not greater than C., depending upon the nature of the thread being dried. In the instant example, it is heated to about 78 C. An initial length of 1.5" of the periphery'of-the reel nearest the siipported end is substantially cylindrical. The next 3.5" of the length of the reel is tapered to allow'for shrinkage of the thread in the absence of substantial tension. The last 1.5" is substantially cylindrical to allow for complete drying of the thread after completion of the shrinkage. Like reel l2, reel I4 is of aluminum.

Under these conditions, no loops form in the thread during the second drying operation,' this even though the-thread is permitted to shrink freely. The thread is characterized by straight filaments of highly uniform characteristics. By contrast, thread which is dried only once, even with substantially unrestrained shrinkage, is characterized by loops in its filaments which not only impair the appearance of the thread but also introduce dlfiiculties in forming the thread into fabric, This fact, together with the fact that on rewettingthe thread absorbs at most considerably less than its original moisture content; e. g., in the neighborhood of one-half of its original moisture content, indicates that a change in the structure of the thread takes place in the course of the first drying operation.

Both the methods and forms 1 of apparatus above described as embodying the invention are susceptible of various modifications without departing from the spirit of the present invention. For example, more drying operations, with intermediate rewetting, may b employed than those specifically disclosed .and other meansfor and methods of rewetting than those illustrated may be used. Either as'disclosed or as modified, the illustrated methods and forms of apparatus may be employed for other uses; for example, the drying of materialsother than textile thread per se. The term thread in the appended claims is intended to include simi ar materials capable of being operated on and handled according to the present invention. e

It is intended that the patent shall cover, by

1. In the manufacture by the viscose process of multiple filament artificial silk thread having highly uniform shrinkage characteristics, the

method of uninterruptedly producing a continu-- ous length of thread characterized by a residual capacity to shrink in the neighborhood of 1% comprising successively performing in one continuous sequence of operations the several steps of extruding viscose into a coagulating bath to form the thread; subjecting the thread so formed to liquid processing treatment; drying the proce essed thread from the gel state; rewetting the dried thread; storing the rewetted thread under conditions permitting excess liquid to drip therefrom; redrying the thread under conditions such that the residual shrinkage capacity of the thread may be fixed at the desired value, meanwhile supporting the thread in the absence of substantial tension in such manner that the thread is free to shrink virtually without restraint; and, after completion of the re-drying operations, collecting the thread in package form, each of said steps other than the first and last being performed on the thread while it is traveling endwise in extended form.

2. A method as in claim 1 including the step of drying the thread from the gel state while supporting it in the absence of substantial tension.

3. A method as in claim 1 including the steps of drying, rewetting and redrying the thread while supporting it in such manner that the tension in the thread remains substantially constant.

4. A method as in claim 1 including the step of drying the thread from the gel state while supporting it rigidly over substantially its entire length to thereby causetension to develop in the thread and to overcome the inherent tendency of the thread to shrink.

5. In the processing of multiple filament viscose artificial silk thread pursuant to a method in which freshly spun thread is passed in sequence over a series of separate thread-advancing reels on each of which the thread is continuously but temporarily stored in a large number of generally helical turns, the steps of heating the thread from the gel state to a condition of substantial dryness while it is stored on a first of said series of thread-advancing reels; passing the dried thread to and rewetting it on a second of said series of thread-advancing reels on which the re-wetted thread is stored in sufllcient length so that over part of the helix, on which part no liquid is applied to the thread, the re-wetting liquid can drip therefrom; and passing the rewetted thread to and reheating it to a condition of substantial dryness on a third of said series of thread advancing reels, meanwhile supporting it in the absence of substantial tension in such manner that it is free to shrink virtually without restraint.

6. In the processing of multiple filament viscose artificial silk thread pursuant to a method in which freshly spun thread is passed in sequence over a series of separate thread-advancing reels on each of which the thread is continuously but temporarily stored in a large number of generally helical turns, the steps of heating the thread from the gel state to a condition of substantial dryness while it'is stored on a first of said series of thread-advancing reels: re-wetting the dried thread, passing it in the meanwhile to "a second of said series of thread-advancing reels on which the re-wetted thread is stored in sufllcient length so that over part at least 0! the helix the re-wetting liquid can drip therefrom; and passing the re-wetted thread to and re-heating it to a condition oi! substantial dryness on a third of said series of thread-advancing reels, meanwhile supporting it in the absence of substantial tension in such manner that it is free to shrink virtually without restraint.

HAYDEN B. KLINE.

LOUIS S. FRYER. 

